WITHOUT THE fine print, it isn't possible to draw any definitive conclusions from the major restructuring of the Department of Homeland Security announced yesterday by the department's secretary, Michael Chertoff. Both in a speech he gave describing the changes and in his subsequent comments, he frankly identified some of his department's most intractable problems, ranging from the urgent need for better information-sharing across the department, to the poor quality of current terrorist watch lists and other screening systems, to the porous southern border. Whether he has a strategy that can solve these issues, some of which predate the department itself, will become clearer as he announces more specific policy changes over the coming weeks.

Nevertheless, the philosophy that lies behind the restructuring is the right one. In a meeting at The Post, Mr. Chertoff repeated several times that the goal of the reform is to keep the department focused on the most serious threats: both those targets that are of most interest to terrorists and those attacks, particularly involving nuclear or biological weapons, that could do the most damage. He spoke, for example, of using computerized risk analysis to determine spending priorities, a principle that would improve on the current, often haphazard decision-making process. At the moment, spending is easily hijacked by Congress: This week the Senate voted in favor of a more risk-based formula for distributing first responder money, but -- thanks to pressure from smaller, less populated and less clearly targeted states -- shied away from taking the principle as far as it should go.

Mr. Chertoff's priority-setting is also important at a moment when many in Congress and elsewhere are calling for large new sums to go to securing mass transit systems in response to the London bombings. While not denying that there were particular issues that might well be addressed with more money, Mr. Chertoff pointed out that there are limits to what technology can currently do: If so much security is built into a subway system or a bus station that it becomes dysfunctional, he said, then "we have lost the war." Besides, it would be wrong to make policy based on "last week's news."

Mr. Chertoff's stress on taking away unnecessary security, as opposed to simply laying on more and more, is also the right one. Among other things, he announced yesterday the lifting of a rule that obliges passengers flying into Reagan National Airport to remain seated for the final 30 minutes of the flight. Better airport security, air marshals and reinforced cockpit doors make the rule unnecessary, Mr. Chertoff said, and the change will certainly be welcomed by travelers.

This homeland secretary is also ready to tell the nation that no security measure is a "guarantee," an important reminder in a war against extremism that is likely to continue for many years. The chief lesson that Mr. Chertoff said he has drawn so far from the London bombings is that a degree of "resilience" is necessary for any nation to successfully survive terrorism. However tempting, panic and overspending cannot be the right reaction to the inevitable attacks to come. We hope Mr. Chertoff can hold to that philosophy as he continues to build the homeland's defenses.